<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title>symbol</title>
	</head>
	<body>
		<script type="text/javascript">
			window.onload(){
				//创建Symbol
				let s =Symbol();
				let s2=Symbol('尚硅谷');
				let s3=Symbol('尚硅谷');
				console.log(s2===s3);//返回false
				
				let s4=Symbol.for('尚硅谷');
				let s5=Symbol.for('尚硅谷');
				console.log(s4===s5);//返回true
				//symobl不能进行运算
				/*
				 * js数据类型
				 * usomb you are so nobility；
				 * u  undefined
				 * s string symbol
				 * o object 
				 * n null number
				 * b bolero
				 * 
				 */
			}
		</script>
	</body>
</html>
